JP2912743B2 - Barcode decoder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code decoder used in a bar code reader.

[0002]

2. Description of the Related Art A bar code reader is constructed as shown in FIG. That is, the light beam from the light source 1 is applied to a polarizer 2 such as a polygon mirror or a vibrating mirror to be polarized and scan on the barcode label 3. After the reflected light from the barcode 3 is detected by the photodetector 4, the analog circuit 5 performs processing such as photoelectric conversion, signal amplification, A / D conversion, etc., and a bar having a time width corresponding to each bar of the barcode. The code digital signal and a binary video signal representing a bar and a space are supplied to the decode processing unit 6.

[0003] A decoding processor 6 decodes a code code based on a bar code digital signal and a video signal.
The transition of the bar and space is delayed at a predetermined interval, and is generated as a character whenever a predetermined condition described later is satisfied.

The condition for recognition as a character is determined by the ratio of the sum of four adjacent bar code digital signals to the sum of the preceding four adjacent bar code digital signals, and is 85% (27/32) in theory. Handle the case where is satisfied.

The relationship between a character, a bar code digital signal, and a video signal is determined under the following conditions. In addition,
Characters represented as numbers 0 to 9 have a general module (minimum unit of bar width or space width) determination method, and a similar parity determination method such as an odd parity can be performed.

The UPC code has a right margin and a guard bar, a left margin and a guard bar, or a center bar for separating left and right character codes (numbers). The condition of a character representing such a special bar will be described. Here, the current decoding position is i, the barcode digital signal is D (i), and the sum of four adjacent barcode digital signals (D (i-3) + D (i-2) + D (i-1) + D ( i)) to S (i),
V (i) for a bar as a video signal, /
V (i) (hereinafter, / is a negative logic symbol). The left margin and guard bar have a left margin of 5 modules or more and a guard bar of 1 module.
Bar is a condition. An equation satisfying this is: / V (i-
1) & V (i) & [S (i + 4) <85% × S (i)] & [3
1.25% × (D (i-3) + D (i-2))> (D (i-1) + D
(i)) is set.

Next, the center bar is distinguished into a left center bar and a right center bar, and left and right characters are divided. Left center bar is 1
The bar space of the module is the bar space. Equations satisfying this are: / V (i-1) & V (i) &
[S (i) <85% × S (i-4)] & [/ V (i-7)] are not the right margin and guard bar. ] & [/ V (i) is not the left margin and guard bar. ] & [/ V (i-4) is not the left margin or guard bar. ] & [S (i + 1) is the number 1
Or 2 or 7 or 8. ] & [S (i) is the number 1, 2, 7 or 8
It is. ] Is set.

The right center bar is conditioned on a space bar space bar of one module. As an expression satisfying this, / V (i) & V (i-1) & [S (i) <85% × S (i +
4)] & [/ V (i + 4) is not right margin or guard bar. ] & [/ V (i) are not right margin and guard bar. ] & [S (i-1) is the number 1, 2, 7, or 8. ] &
[S (i) is the number 1, 2, 7, or 8. ] Is set.

The right margin and the guard bar have a right margin of 5 modules or more and a guard bar of 1 module.
Space bar is a condition. An expression satisfying this is: / V (i-2) & V (i-3) & [S (i-4) <85% × S
(i)] & [31.25% × (D (i) + D (i-1))> (D
(i-1) + D (i-2)).

[0010] The valid character and parity data generated by the decoding processing in the decoding processing section 6 are supplied to a sequence control section 7. This sequence control unit 7
In the above, the four-sequence control focusing on the transition interval of “4” is performed, and the number data and parity data of the left half segment are set using the left margin and guard bar of the effective character as the start character and the left center bar as the stop character. Store. Similarly, the number data and parity data of the right half segment are stored with the right central bar of the effective character as a start character and the right margin and guard bar as stop characters. If a code type table built in the sequence control unit 7 is used, the code type data determined by a parity pattern (array of parity data) can be used.
The data is supplied whenever the CPU 8 requests data by interposing a CPU interface built in the sequence control unit 7.

[0011]

When such a predetermined relationship is used, decoding of the UPC code E type requires
In order to produce the same result as when decoding other six-digit half segments other than UPC-E, the final code type was determined using the code table corresponding to the parity array. However, the barcode digital signal input to the decoder is a signal that has passed through an optical system and an analog circuit. As a result, there is a problem that the UPC-E type code is erroneously read as another six-digit half-segment code.

Accordingly, an object of the present invention is to provide a bar code decoder capable of reliably distinguishing UPC-E type codes from other codes and preventing misreading of bar codes.

[0013]

The invention corresponding to claim 1 is:
A bar code consisting of a bar and a space having at least two kinds of width values is represented by a bar code digital signal corresponding to the width of each bar and each space and a bar and a space,
A bar code decoder that inputs the value as a video signal and decodes the code code of the input signal.
A decoding processing means for decoding an E-type guard bar as a kind of input signal and outputting character data and parity data; and a plurality of parity pattern tables including a UPC-E type, and character data output from the decoding processing means. And determining means for determining whether the character data is valid or invalid by comparing the parity data with a parity pattern of a UPC-E type parity pattern table when the stop character is a UPC-E type guard bar. It is.

According to a second aspect of the present invention, a UPC-E decoding means decodes a UPC-E type guard bar as a kind of input signal and outputs character data, parity data and a flag indicating a bar code type.
Provide multiple parity pattern tables including types,
The character data, parity data and flag output from the decoding processing means are fetched, and the flag is set to UPC-E
When the type flag is set, the parity data is compared with a parity pattern of a UPC-E type parity pattern table to determine whether character data is valid or invalid.

[0015]

In the invention according to the first aspect, the UPC-E type guard bar is also decoded as a kind of the input signal in the decoding processing means, and the character data and the parity data are outputted to the judging means. The determination means determines whether or not the stop character is a UPC-E type guard bar. When the stop character is a UPC-E type guard bar, the parity data is compared with the parity pattern of the UPC-E type parity pattern table to determine the character data. Is valid or invalid.

In the invention according to claim 2, the UPC-E type guard bar is also decoded as a kind of the input signal by the decoding processing means, and character data, parity data and a flag indicating the bar code type are output to the judging means. . The determination means determines whether or not the flag is a UPC-E type flag. When the flag is a UPC-E type flag, the parity data is compared with a parity pattern of a UPC-E type parity pattern table to enable or disable character data. Is determined.

[0017]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the apparatus comprises a decoding processing section 11 as decoding processing means and a sequence control section 12 as judging means. A bar code digital signal having a time width corresponding to each bar of the bar code and a binary video signal representing a bar and a space are input to the decode processing unit 11 from an analog circuit (not shown).

The decoding processing section 11 is provided with a character data determined by a predetermined condition, an error signal which becomes "1" when a decoding result other than the character data is obtained, a transition signal representing a bar and a space when decoded as character data, and Parity data represented by "1" for odd parity and "0" for even parity is supplied to the sequence control unit 12, respectively. Further, a clock that takes operation timing is input to the decode processing unit 11 and the sequence control unit 12.

In the decoding unit 11, the numbers 0 to 9 are directly represented by hexadecimal numbers, the left margin and the guard bar are represented by Ah, the right margin and the guard bar are represented by Bh, the left center bar is represented by Ch, and the right center is represented by Ch. The bar is indicated by Dh, the left margin and the UPC-E guard bar are indicated by Eh, and the right margin and the UPC-E guard bar are indicated by Fh.

The decode processing unit 11 guarantees a sufficient setup / hold time for a bar code digital signal having a time width corresponding to each bar width and a binary video signal representing a bar and space. Delay processing is performed by a clock at the latch timing, and a character is generated whenever a predetermined condition described later is satisfied, and an error signal is output when the condition is not satisfied.

The condition for recognizing a character in the decoding processing unit 11 is determined by the ratio of the sum of four adjacent barcode digital signals to the sum of the preceding four adjacent barcode digital signals, and is expressed by a theoretical value. Handle the case where 85% is satisfied.

The relationship between the character, the bar code digital signal and the video signal is determined under the following conditions. In addition,
Characters represented as numbers 0 to 9 are determined by a general module (the minimum unit of the bar width or the space width).

For ease of explanation, the current decoding position is i, the bar code digital signal is D (i), and the sum of four adjacent bar code digital signals (D (i-3) + D (i-
2) + D (i-1) + D (i)) is represented by S (i), V (i) for a bar as a video signal, and / V (i) for a space as a video signal.

The character Ah (left margin and guard bar) is conditioned on a bar space bar having a left margin of 5 modules or more and a guard bar of 1 module. An expression that satisfies this is: / V (i-1) & V (i) & [S (i +
4) <85% × S (i)] & [31.25% × (D (i-3)
+ D (i-2))> (D (i-1) + D (i)).

The character Bh (right margin and guard bar) is conditioned on a bar space bar having a right margin of 5 modules or more and a guard bar of 1 module. As an expression satisfying this, / V (i-2) & V (i-3) & [S (i
-4) <85% × S (i)] & [31.25% × (D (i) +
D (i-1))> (D (i-1) + D (i-2)).

The character Ch (left center bar) is subject to a space bar space bar of one module. Equations satisfying this are: / V (i-1) & V (i) &
[S (i) <85% × S (i-4)] & [/ V (i-7) is not Bh. ] & [/ V (i) is not Ah] & [/ V (i-
4) is not Ah. ] & [S (i + 1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ]
Set.

The character Dh (right center bar) is conditioned on a bar space bar space of one module. Equations satisfying this are: / V (i) & V (i-1) &
[S (i) <85% × S (i + 4)] & [/ V (i + 4) is not Bh. ] & [/ V (i) is not Bh. ] & [S (i-
1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ] Is set.

Character Eh (left margin and UPC-
(E guard bar) is a condition that a margin of 5 modules or more and a bar space bar space bar of one module are required. An expression that satisfies this is: / V (i) & V (i-
1) & [S (i) <85% × S (i + 4)] & [/ V (i) is Bh
is not. ] & [/ V (i + 4) is not Bh. ] & [S
(i + 1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1
Or 2 or 7 or 8. ] & [/ V (i-4) is Ah. ] Is set.

Character Fh (right margin and UPC-
E-guard bar) is subject to a space bar space bar space bar of one module and a margin of five or more modules. As an expression satisfying this, / V (i
-1) & V (i) & [S (i) <85% x S (i-4)] & [/ V
(i-7) is not Bh. ] & [/ V (i) is not Ah. ] & [S (i-1) is the number 1, 2, 7, or 8. ] &
[S (i) is the number 1, 2, 7, or 8. ] & [/ V (i + 1)
Is Bh. ] Is set.

The valid character and parity data generated by the decoding processing in the decoding processing unit 11 are supplied to the sequence control unit 12. The sequence control unit 12 performs four sequence control focusing on the fact that the transition interval is “4”, and sets the effective character A
h for start character, Dh and Fh for stop
The left half segment number data and parity data are stored as characters. Similarly, the effective character C
h and Eh start character, Bh stop character
The right half segment number data and parity data are stored as characters. The sequence control unit 12
Has a plurality of parity pattern tables such as UPC-E type and EAN-13 type.

If a code type table built in the sequence control section 12 is used, code type data determined by a parity pattern (array of parity data) can be used. The sequence control unit 12
It supplies data via the CPU bus whenever a CPU (not shown) requests data by intervening a CPU interface built into the CPU.

In the embodiment having such a configuration, FIG.
When the UPC-E type barcode label 13 is scanned as indicated by the arrow in the figure, the decoding processing unit 11 makes a character determination based on the character determination condition for each transition of each bar and each space. Assuming that the character Ah, which is the start character, is captured in the cycle of the sequence control unit 12, the effective characters captured in this cycle are "Ah, 0, 1, 2, 2, 3" as shown in FIG.
3, 4, 5, Fh ". The sequence control unit 12 knows that one half segment has been obtained when the character Fh, which is the stop character, is recognized. At this time, parity data is also captured at the same time. Then, the sequence control unit 12 stores character data and parity data representing the number surrounded by the start and stop characters, and further stores the parity pattern “E, 0,
The code type is determined based on "E, 0, E, 0" with reference to the parity pattern table.

At this time, since the stop character is the character Fh, the sequence controller 12 selects and refers to the UPC-E type parity pattern table 14 shown in FIG. Thereby, this code determines that the prefix character of the UPC-E type is a code of "7".

On the other hand, the bar code digital data obtained by scanning the bar code label 13 undergoes a slight change due to optical and electrical influences.
As shown in FIG. 5, when the effective character becomes "Ah, 4,1,2,3,4,1, Fh" as shown in FIG. 5, this effective character is captured by the sequence controller 12 together with the parity data. You. Then, the sequence control unit 12 knows that one half segment has been obtained when the character Fh is recognized. As a result, the sequence control unit 12 stores character data and parity data representing the number surrounded by the start and stop characters, and furthermore, the stop character is the character Fh
Therefore, the UPC-E type parity pattern table 14 is selected and referred to. However, the parity pattern this time is “0, 0, E, 0, E, E” and this parity pattern does not exist in the parity pattern table 14. Thus, the sequence control unit 12 determines that the barcode is not a UPC-E barcode and invalidates the data.

The parity pattern this time is "0,
As shown in the EAN-13 type parity pattern table 15 in FIG. 6, "0, E, 0, E, E" matches the parity pattern whose prefix character is "1". Therefore, if the parity pattern table to be referred to is an EAN-13 type parity pattern table 15,
If you do, misreading will be done. However, in the present embodiment, such misreading is surely prevented. Next, another embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 7, a decoding processing unit 11 'as a decoding processing unit, a sequence control unit 12' and a CPU (central processing unit) 16 constituting a judgment unit are provided.
It is composed of A bar code digital signal having a time width corresponding to each bar of the bar code and a binary video signal representing a bar and a space are input from an analog circuit (not shown) to the decode processing unit 11 '.

The decoding section 11 'is a character signal determined according to predetermined conditions, an error signal which becomes "1" when decoding results other than character data, and a transition signal representing a bar and space when decoded as character data. Parity data represented by "1" for odd parity and "0" for even parity is supplied to the sequence control unit 12 '.

In the decoding processing unit 11 ', the numbers 0 to 9 are indicated by hexadecimal numbers as they are, the left margin and guard bar are indicated by Ah, the right margin and guard bar are indicated by Bh, the left center bar is indicated by Dh, and the right center bar is indicated by Dh. The center bar is indicated by Eh, and the character indicating an error outside the above conditions is indicated by Fh.
It is indicated by. The UPC-E type guard bar and the right margin are indicated by a flag FINE.
-Flag FOU with E type guard bar and left margin
It is indicated by TE.

The decode processing section 11 'guarantees a sufficient setup and hold time for a bar code digital signal having a time width corresponding to each bar width and a binary video signal representing a bar and space. Delay processing is performed by a clock of the latch timing, and a character is generated whenever a predetermined condition described later is satisfied, and an error character Fh is output when the condition is not satisfied. At this time, the flags FINE and FOUTE are simultaneously decoded.

The condition for recognizing a character in the decoding unit 11 'is determined by the ratio of the sum of four adjacent barcode digital signals to the sum of the preceding four adjacent barcode digital signals, and 85%
Handle the case where is satisfied.

The relationship between the character, the bar code digital signal, and the video signal is determined under the following conditions. In addition,
Characters represented as numbers 0 to 9 are determined by a general module (the minimum unit of the bar width or the space width).

Here, for ease of explanation, the current decoding position is i, the bar code digital signal is D (i), and the sum of four adjacent bar code digital signals (D (i-3) + D (i-
2) + D (i-1) + D (i)) is represented by S (i), V (i) for a bar as a video signal, and / V (i) for a space as a video signal.

The character Ah (left margin and guard bar) is conditioned on a bar space bar having a left margin of 5 modules or more and a guard bar of 1 module. An expression that satisfies this is: / V (i-1) & V (i) & [S (i +
4) <85% × S (i)] & [31.25% × (D (i-3)
+ D (i-2))> (D (i-1) + D (i)).

The character Bh (right margin and guard bar) is conditioned on a bar space bar having a right margin of 5 modules or more and a guard bar of 1 module. As an expression satisfying this, / V (i-2) & V (i-3) & [S (i
-4) <85% × S (i)] & [31.25% × (D (i) +
D (i-1))> (D (i-1) + D (i-2)).

The condition of the character Dh (left center bar) is a space bar space bar of one module. Equations satisfying this are: / V (i-1) & V (i) &
[S (i) <85% × S (i-4)] & [/ V (i-7) is not Bh. ] & [V (i) is not Ah. ] & [V (i-4)
Is not Ah. ] & [S (i + 1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ] Is set.

The character Eh (right center bar) is conditioned on a bar space bar space of one module. Equations satisfying this are: / V (i) & V (i-1) &
[S (i) <85% × S (i + 4)] & [/ V (i + 4) is not Bh. ] & [/ V (i) is not Bh. ] & [S (i-
1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ] Is set.

As a condition of the UPC-E flag, the flag FINE is required to have a margin of 5 modules or more and a bar space bar space bar of one module. Equations satisfying this are: / V (i) & V (i-1) &
[S (i) <85% × S (i + 4)] & [/ V (i) is not Bh. ] & [/ V (i + 4) is not Bh. ] & [S (i +
1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ] & [V (i-4) is Ah. ] Is set.

The flag FOUTE is conditioned on a space bar space bar space bar of one module and a margin of five or more modules. An expression satisfying this is: / V (i-1) & V (i) & [S (i) <85% × S (i-
4)] & [/ V (i-7) is not Bh. ] & [/ V (i)
Is not Ah. ] & [S (i-1) is the number 1, 2, 7, or 8. ] & [S (i) is the number 1, 2, 7, or 8. ] &
[/ V (i + 1) is Bh. ] Is set.

The valid character, UPC-E flag, and parity data generated by the decoding process in the decoding unit 11 'are supplied to the sequence control unit 12'. The sequence control unit 12 'performs four sequence control focusing on the fact that the transition interval is "4", and sets the effective character Ah to the start character,
The number data and parity data of the left half segment are stored using h as a stop character. Similarly, the number data and parity data of the right half segment are stored with the effective character Dh as the start character and Bh as the stop character.

By interposing a CPU interface built in the sequence control section 12 ',
Whenever the PU 16 requests data, it supplies the data via the CPU bus. The CPU 16 has a UPC
A plurality of parity pattern tables such as -E type and EAN-13 type are provided.

In this embodiment, when a UPC-E type bar code label is scanned, the decoding processing section 1
In 1 ', character determination is performed according to the character determination condition for each transition of each bar and each space. Assuming that the character Ah, which is the start character, is captured in the cycle of the sequence control unit 12 ', the effective characters captured in this cycle are "Ah, 0,
1, 2, 3, 4, 5, Eh ". The sequence control unit 12 'knows that one half segment has been obtained when the character Eh, which is the stop character, is recognized. At this time, parity data is also captured at the same time. Then, the sequence control unit 12 ′ stores character data and parity data representing the number surrounded by the start and stop characters and supplies them to the CPU 16.

The CPU 16 determines the parity pattern "E, 0,
The code type is determined based on "E, 0, E, 0" with reference to the parity pattern table. At this time, CPU1
FIG. 4 shows that the UPC-E flag is FOUTE.
UPC-E type parity pattern table 1
Select 4 for reference. This makes this code a UPC
-Determine that the E-type prefix character is a code of "7".

On the other hand, the bar code digital data obtained by scanning the bar code label undergoes some changes due to optical and electrical influences, and the result of decoding by the decode processing unit 11 'is as shown in FIG. Assuming that the valid character is "Ah, 4, 1, 2, 3, 4, 1, Eh", the valid character is captured by the sequence controller 12 'together with the parity data. When the sequence controller 12 'acquires one half segment, the sequence controller 12' stores character data and parity data representing the number surrounded by start and stop characters, and
6

Since the UPC-E flag is FOUTE, the CPU 16 selects and refers to the UPC-E type parity pattern table 14 shown in FIG.
However, the parity pattern this time is "0, 0, E, 0,
E, E ", this parity pattern does not exist in the parity pattern table 14. Then, CPU16 is UP
Judge that the bar code is not a CE bar code and invalidate the data. Therefore, in this embodiment, the same effects as those of the above embodiment can be obtained.

[0056]

As described in detail above, according to the present invention, U
It is possible to provide a bar code decoder capable of reliably distinguishing a PC-E type code from other codes and preventing a bar code from being erroneously read.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a UPC-E barcode and its scanning in the embodiment.

FIG. 3 is an exemplary view showing characters and parity data of a UPC-E barcode in the embodiment.

FIG. 4 is an exemplary view showing a UPC-E type parity pattern table in the embodiment.

FIG. 5 shows an UP in which data has changed in the embodiment.
The figure which shows the character of CE barcode, and parity data.

FIG. 6 is a view showing an EAN-13 type parity pattern table in the embodiment.

FIG. 7 is a block diagram showing another embodiment of the present invention.

FIG. 8 is a view showing characters and parity data of a UPC-E barcode in the embodiment.

FIG. 9 shows an UP in which data has changed in the embodiment.
The figure which shows the character of CE barcode, and parity data.

FIG. 10 is a block diagram showing a configuration of a conventional barcode reading device.

[Explanation of symbols]

11: decoding processing unit, 12: sequence control unit, 14
... UPC-E type parity pattern table.

Claims (2)

(57) [Claims] 1. A bar code consisting of bars and spaces having at least two kinds of width values is input as a bar code digital signal corresponding to each bar and each space width and a binary video signal representing the bars and spaces. In a bar code decoder for decoding a code code of the input signal, a UPC-E type guard bar is decoded as a kind of the input signal, and decoding processing means for outputting character data and parity data; A parity pattern table is provided, and character data and parity data output from the decoding processing means are fetched.
In the case of E type guard bar, parity data is
A bar code decoder characterized by further comprising a judging means for judging validity / invalidity of character data by comparing with a parity pattern of a CE type parity pattern table. 2. A bar code consisting of bars and spaces having at least two kinds of width values is inputted as a bar code digital signal corresponding to the width of each bar and each space and a binary video signal representing the bars and spaces. A bar code decoder for decoding a code code of the input signal, decoding a UPC-E type guard bar as a kind of input signal, and outputting character data, parity data and a flag indicating a bar code type; A plurality of parity pattern tables including the -E type, and taking in the character data, the parity data and the flag output from the decoding processing means, and when the flag is a UPC-E type flag, the parity data is stored in the UPC-E type. Parity of parity pattern table A bar code decoder characterized by further comprising a judging means for judging validity or invalidity of character data by comparing with a character pattern.